Engineering Advanced Electrolyte and Metal Organic Framework Catalyst for Lithium Batteries

With a potential specific energy of more than 3,500 Wh.kg-1, lithium-oxygen batteries are regarded as an excellent choice for next-generation energy storage, competing with gasoline. However, the inherent instability of liquid electrolytes, the flammability risks associated with volatile solvents, and the insulating nature of the discharge product, lithium peroxide, which severely restricts operation to low current densities, are currently impeding the practical realization of this technology. The development of a highly conductive polymer-in-salt quasi-solid-state electrolyte (PS-QSSE) and the engineering of a high-entropy metal-organic framework (MOF) cathode catalyst to significantly change the discharge reaction pathway are the two main strategies used in this dissertation to overcome these significant obstacles. First, 1-methyl-3-propylimidazolium iodide (MPII) ionic liquid was added to a PVDF-HFP polymer backbone containing high-concentration LiTFSI salt to create a new PS-QSSE. By effectively preventing salt precipitation and inducing a suitable polymer beta-phase, the ionic liquid addition produced channels with locally high concentrations of lithium cations. This architecture showed strong stability against lithium metal anodes and produced an extraordinary ionic conductivity of 28.4 mS.cm-1 which is nearly 47 times greater than liquid counterparts. With a low charge potential, the electrolyte allowed a lithium oxygen battery to run for more than 500 cycles at 0.1 mA.cm-2. Following on this foundation, the study aimed to address cathode passivation in order to enable ultra-high current capabilities. Using a liquid-liquid interface technique, a ternary high-entropy MOF (NiMnCo-BHT) was made to function as a high-performance cathode catalyst. This catalyst enabled a transition from the traditional two-electron pathway to a one-electron pathway when combined with an improved PS-QSSE (conductivity enhanced to 37 mS.cm-1). This change prevented pore clogging and electrode passivation by stabilizing the generation of conductive lithium superoxide instead of insulating lithium peroxide. As a result, stable battery operation at the current density of 3 mA.cm-2 was made possible by the synergistic integration of the improved electrolyte and the HE-MOF catalyst. These results set a new standard for high-rate lithium oxygen batteries and offer a scalable route toward secure, storage systems with high energy density that can satisfy the demanding requirements of electric vehicles of the future.

Author dc:creator

• Arash Namaeighasemi (22693941)

• Battery
• Energy

Statement dc:rights

• In Copyright
• Open Access after 2028-05-01

DOI dc:identifier

https://doi.org/10.25417/uic.32995076.v1

OAI identifier oai:identifier

oai:figshare.com:article/32995076